Flash bulbs, electronic flash, and Kodak Supermatic flash shutters?

I have a Flash Supermatic that works with an electronic flash. Well, two of three- a Vivitar 225 and 285 both fire, but a Vivitar 3900 doesn't.

Also have a Heiland flashbulb gun that simply will not fire. The shutter has an escapement delay mechanism. On some Kodak shutters I have seen a resistor tied into the circuit, connecting the hot pin to the ground.

All in all I have little understanding of flash circuits and old leaf shutters. The actual connection on these shutters is a pin in the blade mechanism that contacts a piece of spring brass that is connected to the hot pin. So the shutter travels to full open, the circuit is closed, (flash fires???), circuit opens. A simple switch. But then the function of the resistor on some versions of this shutter confuses me...

That’s not my favorite shutter so I don’t use them, but if I’m not mistaken the resistor is integral to the x-synch circuit.

You can probably figure it out with this resource:

See this thread: https://www.photrio.com/forum/threads/issue-with-kodak-flash-supermatic-shutter.88819/
also the remark in the manual Brian linked about whether or not a connection to chassis ground prevents a flash from firing (just flashbulbs, or electronic flash as well? No idea).

There are a couple of issues, one is can you trust the shutter to fire at X-sync just by not cocking the flash sync delay mechanism or do you need to do something additional. Another is what is the resistor doing - it seems to be something about semi-isolating the flash contact pin from chassis ground when cocking the shutter, but I really don't have a confident answer to that.